If my son was a passanger in a car and was killed, should I consult with a lawyer?

I am so sorry to hear about your loss.  If you wish to pursue a wrongful death claim against the at fault driver for the accident, I would strongly suggest you contact a personal injury attorney in your area.  Handling these types of claims on your own can be difficult and time consuming.  A personal injury attorney will be able to hear all of the facts of your case and help you decide what your best legal option is at this point.  I wish you the best!